OGSA Transition
• Widely adopted Grid Middleware
• Result of 5+ years (100+ man years) work
• Provides protocols to support three services:
ATF Migration Strategy
– Job Submission and Monitoring (~HTTPS)
– Monitoring and Discovery Service (~LDAP)
– Data Transfer (~FTP)
Dr Steven Newhouse, Technical Director
London e-Science Centre
• Infrastructure to federate distributed resources
– Support for access control
– Wide area security mechanisms (PKI)
Department of Computing, Imperial College London
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• Increasingly popular standards-based framework for
accessing network applications
– W3C standardization; Microsoft, IBM, Sun, others
• XML: Extensible Markup Language
– Network portable structured information
• WSDL: Web Services Description Language
•
•
•
•
– Interface Definition Language for Web services
Globus: Grid Index Information Service (LDAP)
Jini: Look-up Server
CORBA
Web Services
• SOAP: Simple Object Access Protocol
– XML-based RPC protocol; common WSDL target
• UDDI: Universal Description, Discovery, & Integration
– Directory for Web services
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• Utilise standard Web services infrastructures
• Dynamic Services
– Enables resource virtualisation
– Created & destroyed on user demand
• Building on capability within GT2:
• Stateful Services
–
–
–
–
– Expose internal service state
• Flexible Service Discovery Infrastructure
– Scalable to 1000’s services across multiple
locations
– Build Virtual Organisations on demand
– MyVO: The services I have access to
Grid Service: semantics for service interactions
Management of transient instances (& state)
Factory, Registry, Discovery, other services
Reliable and secure transport
• Multiple hosting targets: J2EE, .NET, …
• Reference implementation Globus Toolkit 3 (GT3)
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‘Architect’s view of the completed building’
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• Grid Services Specification (v1.0),
• Define minimal set of ports & behaviours:
– Produced by the GGF OGSI Working Group
– Entered 60 day comment period March 2003
– Wide engagement: Academic & Industry participation
– Creation, destruction, notification, registration etc.
• Defined other standards activity in GGF:
• Specifies:
–
–
–
–
– Exposing an EJB as a Grid Service
– Security (authentication, authorisation,
accounting)
Web Services with Grid Behaviours (i.e. richer structure)
Service creation & life-time management
Service Data to feed into Grid Information Services
Hosting Environment
• Provides component model for web services
• Creation, Resource allocation, monitoring
• Control and Data transport
• GT3 as reference implementation July 2003
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‘Bricks & mortar to construct a building’
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Data Intensive X Scientists
• OGSI:
– Defines how the service interface behaves
– Defines interaction between service & container
Data Intensive Applications for Science X
Simulation, Analysis & Integration Technology for Science X
• OGSA:
Generic Virtual Data Access and Integration Layer
– Defines the platform (collection of services)
• Computer centre
• Data centre
Job Submission
Brokering
Registry
Banking
Data Transport
– Services can be defined and evolve elsewhere
Workflow
OGSA
Authorisation
Structured Data
Integration
Resource Usage Transformation Structured Data Access
OGSI: Interface to Grid Infrastructure
• ‘Approved’ by OGSA-WG/GGF
• ‘User Contributed’ from the community
Compute, Data & Storage Resources
Structured Data
Relational XML Semi-structured
Distributed
Virtual Integration Architecture
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• No hurry!
• Existing GT2 users
– Commitment to support GT2 until end 2003 (at least)
– GT2 client-side C library to wrap GT3 interface
– Early adopters of GT3 will have to work harder
– GT2 is established and understood
– When to move?
• Existing web service users
• Attractions
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–
–
–
–
–
– Reliable commercial infrastructures
– Why & when to move?
• New users
– Adopt something new (GT3) or understood
(GT2 / web services)
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Standards driven architecture
Smaller service granularity & defined framework
Easier for projects to contribute to GT3
‘Proper’ software engineering process
Access to web services and tools
Wider range of supported platforms
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• A Grid Service is a Web Service
• Consider using GT3 but with caution…
– Have to add the Grid Service PortTypes
– Should be easy iff
– New software
• Release Summer 2003
• Mature stable releases probably not until Q1 2004
• Appropriate libraries & tools to support migration are developed
• Support may be language dependent:
– By January 2004
– Java & C: Probably well supported
– C++ & C#: Support currently not clear
• Better Documentation
• More Experience
• Supported Services
• Issues
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–
–
–
Will the same registries be used?
What are the minimum required Service Data Elements?
Which hosting platforms will work?
Which Web Service tools will work with Grid Services?
– OK to design and do some prototypes now?
• OGSI stable except in the area of notification
• OGSA intensive efforts underway
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• Combinatorial effects of composing services
• Technical Support
– What will be a sensible core combination?
– On what hosting environments and platforms?
– Grid Support Centre
– Engineering Task Force
• Need to explore, evaluate & assess a variety of:
• Training Provision from e-Science Institute
– Services
– Hosting Environments
– Platforms
– Primers and guides on Web Sites
– Hands-on developer courses
– Orientation, Planning & Management
• Driven by real examples:
• For Project Leaders, Designers and Architects
– Composed services within workflow
– Code/WSDL examples
– Test Deployment and Operation
– Schedule to match GSC + ETF + Project’s activities
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GT2 service + GT3 preparatory investigations
GT2 service + GT3 prototyping & support
GT2 service + GT3 service
GT3 service
Proposed transition
from GT2 to GT3
Level 3
GT3
L2
Level 1
Level 0
GT2
Level 3
L2
Level 1
Level 0
Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2
2001
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2002
2003
2004
2005
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• OGSI/OGSA will provide real benefits
• But there are still issues to be resolved:
– OGSA definition / delivery
– Hosting environments & platforms
– Combinations of Services supported
– Material and Grids to support adopters
– Resources to support transitions
• Community outreach: www.nesc.ac.uk
Comments & Questions?
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